12 FISH AND GAME COMMISSION. 



mine whether Sacramento salmon are taken along the Mendocino Coast. 

 The returned marked fish, through microscopic examination of the 

 scales, have furnished additional evidence as to the age and growth of 

 king salmon. IMuch data has also been gathered at the various salmO'U 

 fishing centers. Six-months-old salmon, marked at the Mount Shasta 

 Hatchery by the removal of certain fins, have been taken three and four 

 vears later along the northern California coast. 



The information obtained from this investigation comes at an oppor- 

 tune time for there is every evidence that the salmon fishery is depleted 

 and that present laws are inadequate to conserve the fishery. 



Dredging operations in San Pablo Bay, by destroying the food supply 

 of the striped bass, have driven this fish elsewhere. Furthermore, it is 

 evident that the striped bass fishery is in danger because of the decreas- 

 ing number of large fish taken during the open season. Since salmon 

 and striped bass are caught by the same fishing methods, plans are 

 being made to give additional protection to the striped bass along with 

 the salmon. 



A report on the edible clams, mussels and scallops of California has 

 been published as Fish Bulletin No. 4. This records the results of 

 investigations of the shellfish resources of the state, and includes recom- 

 mendations as to their conservation. Furthermore, the results of a 

 careful study of the pismo clam, one of our most important mollusks, 

 is ready for publication. It includes the first detailed study of the life 

 history of this clam, together with a report on habits, age, rate of 

 growth, and fluctuations in abundance. It is hoped that these investi- 

 gations will furnish sufficient data to assure the conservation of this 

 valuable resource. 



Publication of the results of the albacore investigations, instituted 

 several years ago, has been delayed because of the additional data which 

 it has been found desirable to include. It has been found difficult to 

 determine whether evidences of decreasing abundance of albacore are 

 due to actual depletion from over-fishing or indicate simply a fluctua- 

 tion due to natural causes. Important discoveries have furnished evi- 

 dence as to the age and rate of growth, time of spawning and distribu- 

 tion of this valuable food fish. It has been most encouraging to obtain 

 results of such great use to the fish industry. 



The sardine investigation has also been productive of valuable data 

 as to the natural fluctuation, migration, age, rate of growth, breeding 

 season and distribution. For a period of two years, daily samples of 

 sardines have been taken, on which careful weights and measurements 

 have been made and the sex and maturity observed. As a result, it 

 has been possible to work out the rate of growth during the first four or 

 five years, information of great importance from the conservation 

 standpoint. 



The establishment of purse seine fishing in southern California 

 created an important problem, for several of the fishermen's organiza- 

 tions have sought to abolish this type of net, maintaining that it was too 

 destructive and endangered fishing institutions. An investigation has 

 sliown that the purse seine boats are not making money and a regulation 

 of the size of nets will put them out of business. Purse seine boats are 

 depended upon to furnish blue-finned tuna for the canneries, and for 



